Cryptic messages from weird oracles or other strange sources can be an endless source of fun in a campaign. Of course the players are going to (a) misinterpret any real message you attempt to convey via them, and (b) come up with all sorts of amazing conspiracy theories as to what the message really means.

Naturally this means you can either stick to your guns have the players end up dead wrong when the time of the prophecy or whatever comes around; or you can simply do the trick of adopting whatever spurious theory the players come up with which sounds the coolest, and turning that into the reality within the game.